It turns out it was colour-ringed by Chris McGuigan last year as part of only six birds (three breeding pairs) at a Dundee supermarket car park. This bird, a female '108', was paired to male '101'. She was ringed ringed on 17 June 2016 and last seen on 11 July 2016.
At least four have returned this year (including 101). A couple were seen to over-winter on the Tay estuary so it was assumed that these birds did not move far. So the Hilbre sighting is a somewhat surprising and interesting development.
Thanks to Matt Thomas and Chris McGuigan for the info. Photo by @mattthomas966 taken at Hilbre on 13 June 2017.